Bone screw and tool for use therewith

ABSTRACT

A bone screw comprises a main body including a shank portion, a head portion attached to the shank portion, and a cap moveably attached to the head portion. The head portion includes a tool interface structure therein having a closed end portion, an open end portion and sidewall extending therebetween. A tool lock recess is provided in at least one of the sidewalls of the tool interface structure. The tool interface structure is accessible through an opening within an exterior surface of the cap.

FIELD OF THE DISCLOSURE

The disclosures made herein relate generally to threaded fasteners and,more particularly, to bone screws and associated tools configured foruse in surgical procedures.

BACKGROUND

It is well-known that there are various diagnoses for which it is neededor desired to hold bones within a human or animal body in a fixedposition with respect to each other. One such diagnosis for which it isdesired to hold bones within a human or animal body in a fixed positionwith respect to each other is an accidental or intentional fracture of abone. Another such diagnosis for which it is desired to hold boneswithin a human or animal body in a fixed position with respect to eachother is in a surgical fusion procedure (e.g., a sacroiliac fusion).

Irrespective of the diagnosis leading to the need or desire to holdbones within a human or animal body in a fixed position with respect toeach other, one or more bone screws are well-known to be used for suchpurpose. The bone screws, which are often used in combination with otherfastening implements (e.g., bone plates) can be threadedly inserted intothe two or more separate bone pieces (e.g., two or more different bonesand/or segments of a given bone) for securing such two or more separatebone pieces in fixed relationship with respect to each other. The bonescrew(s) thereby hold(s) the bone pieces in a stationary position withrespect to each other and, in some usages, thereby allows bone materialto grow therebetween to fuse the bone pieces together. Such bone growthsupplements the strength provided by the bone screw to prevent the bonespieces from moving with respect to each other.

A specific application for bone screws is sacroiliac joint fusion. Asshown in FIG. 1, the sacroiliac (SI) joint 10 is located in the humanbody between the sacrum 11 and the hip bones 12, known as the ilium. Thesacroiliac joint functions to transmit forces from the spine 14,including vertebrae 14 a, intervertebral discs 14 b and the coccyx 14 c,to the lower extremities. The sacroiliac joint 10 is supported byligaments and muscle. The sacroiliac joint 10 can degenerate over time,requiring a fusion procedure to stabilize the degenerated segment. Forexample, one condition, degenerative sacroiliitis, results in a narrowjoint space with bone spur formation. Iatrogenic (i.e., induced bytreatment) procedures, such as iliac bone graft damaging ligaments ofthe joint and/or previous fusions, can also cause degeneration,requiring sacroiliac joint fusion. Alternatively, infection, ligamentousdisruption due to pregnancy, and/or trauma causing fracture dislocationmay require a sacroiliac joint fusion procedure to provide sufficientstabilization to allow the patient to achieve a normal lifestyle.

Therefore, a bone screw for securing bones within a human or animal bodyin a fixed position with respect to each other and that does not inhibitgrowth of bone material between such bone pieces is advantageous,desirable and useful.

SUMMARY OF THE DISCLOSURE

Embodiments of the present invention are directed to a bone screw forsecuring bones within a human or animal body in a fixed position withrespect to each other. Preferably, embodiments of the present inventiondo not inhibit growth of bone material between such bone pieces and,more preferably, promote the growth of bone material between such bonepieces and around/through the bone screw. A bone screw in accordancewith an embodiment of the present invention is further configured with atool locking structure that is in combination with a torque-applyingstructure of the bone screw used for placing and extracting the screw.Such tool locking structure advantageously allows the bone screw to beboth placed (i.e., rotated in a first direction) and extracted (i.e.,rotated in a second direction opposite the first direction) with acommon tool (i.e., a placement/extraction tool). The ability to extract(e.g., unscrewed and retracted from a placement location) a bone screwwith the same tool used for placing such bone screw is highly beneficialsuch as due to time savings during a surgical procedure and isadvantageous with respect to prior art bone screw configurations thatrequire separate placement and extraction tools.

In one embodiment of the present invention, a bone screw comprises ashank portion and a head portion. The shank portion has a proximal endand a distal end. The shank portion includes at least one thread on anexterior surface thereof extending from adjacent the proximal end of theshank portion to adjacent the distal end of the shank portion. The headportion is attached to the shank portion at the proximate end thereof.The head portion includes a tool interface structure therein. The toolinterface structure includes a plurality of sidewalls, a floor and atool lock recess located within at least one of the sidewalls.

In another embodiment of the present invention, a bone screw comprises amain body including a shank portion, a head portion attached to theshank portion, and a cap moveably attached to the head portion. The headportion includes a tool interface structure therein having a closed endportion, an open end portion and a sidewall extending therebetween. Atool lock recess is provided in at least one of the sidewalls of thetool interface structure. The tool interface structure is accessiblethrough an opening within an exterior surface of the cap.

In another embodiment of the present invention, a bone screw comprises ashank portion, a head portion, and a cap. The head portion is attachedto the shank portion at a proximal end of the shank portion. The cap ismoveably attached to the head portion. The shank portion has at leastone helically shaped thread on an exterior surface thereof. The threadextends from adjacent the proximal end of the shank portion to adjacenta distal end of the shank portion. The shank portion includes acannulation passage extending longitudinally therethrough. Thecannulation passage defines an interior surface of the shank portion.The shank portion includes at least one bone material aperture thereinextending between the exterior surface of the shank portion and theinterior surface of the shank portion such that an aperture sidewall isdefined between the exterior surface of the shank portion and theinterior surface of the shank portion. The head portion includes a toolinterface structure therein. The tool interface structure includes aclosed end portion, an open end portion and sidewalls extendingtherebetween. The tool interface structure includes a tool lock enablingfeature provided in at least one of the sidewalls thereof. Thecannulation passage is exposed at the closed end portion of the toolinterface structure. The tool interface structure is accessible throughan opening within an exterior surface of the cap.

These and other objects, embodiments, advantages and/or distinctions ofthe present invention will become readily apparent upon further reviewof the following specification, associated drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view showing a sacroiliac joint and associatedskeletal structure of a human;

FIG. 2 is a first perspective view showing a bone screw in accordancewith an embodiment of the present invention;

FIG. 3 is a second perspective view of the bone screw shown in FIG. 2;

FIG. 4 is a third perspective view of the bone screw shown in FIG. 2;

FIG. 5 is a cross-sectional view taken along the line 5-5 in FIG. 4;

FIG. 6 is a cross-sectional view taken along the line 5-5 in FIG. 4;

FIG. 7 is an exploded view of the bone screw shown in FIG. 2;

FIG. 8 is a cross-sectional view taken along the line 8-8 in FIG. 7;

FIG. 9 is a perspective view of a screw manipulation tool in accordancewith an embodiment of the present invention;

FIG. 10 is a fragmentary perspective view of a screw engagement endportion of the screw manipulation tool shown in FIG. 9, wherein a screwretention member is in an unlocked orientation

FIG. 11 is a fragmentary perspective view of the screw engagement endportion of the screw manipulation tool shown in FIG. 9, wherein thescrew retention member is in a locked orientation;

FIG. 12 is a perspective view of the screw manipulation tool shown inFIG. 9, wherein the screw engagement end portion thereof has the bonescrew of FIGS. 2-8 engaged therewith; and

FIG. 13 is a cross-sectional view taken along the line 13-13 in FIG. 12.

DETAILED DESCRIPTION

Referring now to FIGS. 2-8, various aspects of a bone screw 100configured in accordance with an embodiment of the present invention areshown. The bone screw 100 can be used for securing bones (i.e., bonepieces including fragments/segments of one or more bones) within a humanor animal body in a fixed position with respect to each other. The bonescrew 100 is configured in a manner that promotes the growth of bonematerial between such bone pieces and around/through the bone screw 100(e.g., via self-harvesting of bone particles). The bone screw 100 isconfigured with a torque-applying structure 102 used for its placementand extraction. The torque-applying structure 102 is configured to allowthe bone screw 100 to be both placed (i.e., rotated in a firstdirection) and extracted (i.e., rotated in a second direction oppositethe first direction) with a common tool (i.e., a screw manipulationtool). The ability to extract the bone screw 100 with the same tool usedfor placing it is highly beneficial due to, for example, time savingsduring a surgical procedure and, thus, is advantageous with respect toprior art screw configurations that require placement and extractiontools to be differently configured.

The bone screw 100 comprises a threaded fastener 103 and a cap 104. Thethreaded fastener comprises a shank portion 106 and a head portion 108.The shank portion 106 includes a proximal end 110 and a distal end 112.The head portion 108 is attached to the shank portion 106 at theproximal end 110 thereof. As is well known in the art, the shank portion106 and the head portion 108 are typically concentrically arranged alonga common longitudinal axis LA.

The cap 104 is moveably attached to the head portion 108. In preferredembodiments, the head portion 108 is spherically-shaped and the cap 104includes a mating spherically-shaped receptacle 114 (best shown in FIG.7) that is seated on the head portion 108. The shank portion 106 has athread 116 on an exterior surface 118 thereof. The tread 116 extendsaround the exterior surface 118 of the shank portion 106 in a helicalfashion to thereby form a helically-shaped thread. The thread 116extends from adjacent the proximal end 110 of the shank portion 106 toadjacent a distal end 112 of the shank portion 106.

The tool interface structure 102 is located within the head portion 108.An opening 121 within an exterior surface of the cap 104 enables accessto the tool interface structure 102. Advantageously, the tool interfacestructure 102 being located in the head of the screw as opposed to theshank of the screw enhances its size and resulting strength. Suchenhanced size and strength serves to resistance to stripping out duringinsertion or extraction.

The tool interface structure 102 includes a closed end portion 122, anopen end portion 124 and sidewalls 126 extending therebetween. Theclosed end portion 122 can terminate at a floor of the tool interfacestructure 102 and the open end portion 124 can terminate at a topsurface of the head portion 108. The sidewalls 124 can be a plurality ofsidewall portions that jointly form a contiguous sidewall. The toolinterface structure 102 can include a plurality of tool lock recesses128 each located within a respective one of the sidewalls 126 or caninclude a single tool lock recess 128 associated with one of thesidewalls 126. In some embodiments, the tool lock recess 128 ispartially defined by the above-mentioned floor of the tool interfacestructure 102. The sidewalls 126 of the tool interface structure 102 canhave the profile commonly referred to as a Phillips drive, a Torx drive,an Allen (i.e., hex) drive, a square drive or the like. As best shown inFIG. 8, each tool lock recess 128 is preferably located within a portionof the sidewall 126 that is inboard of a perimeter region of the toolinterface structure 102 as defined by a circle that circumscribes thesidewalls 126.

Each tool lock recesses 128 is an example of a tool lock enablingfeature. Such feature enables the bone screw 100 to be fixedly engagedwith a mating portion of a screw manipulation tool. In view of thedisclosures made herein, a skilled person will appreciate that the toollock enabling feature can be embodied in a variety of configurationsdifferent than a recess as shown.

The shank portion 106 includes a cannulation passage 130 extendinglongitudinally therethrough. The cannulation passage 130 defines aninterior surface 132 of the shank portion 106. The cannulation passage130 is exposed at the closed end portion 122 of the tool interfacestructure 102 (e.g., at the floor of the tool interface structure 102),thereby allowing the bone screw 100 to be placed onto and slid along aguide member such as a wire or trocar.

As best shown in FIG. 7, the shank portion 106 includes a plurality ofbone material apertures 134, 136 extending between the exterior surface118 of the shank portion 106 and the interior surface 132 of the shankportion 106 such that an aperture sidewall 138 of each of the apertures134, 136 is defined between the exterior surface 118 of the shankportion 106 and the interior surface 132 of the shank portion 106.Preferably, the bone material apertures 134, 136 extend through thethread 116 over a first partial length L1 of the shank portion 106 andthe thread 116 extends over a second partial length L2 of the shankportion 106. Preferably, the first partial length L1 is shorter than thesecond partial length L2. For example, each bone material aperture 134,136 extends through the thread 116 over at least a portion of an entirelength of the shank portion 106. Preferably, the second partial lengthL2 encompasses the first partial length L1. Preferably, the firstpartial length L1 begins at a first distance D1 from the proximate end112 of the shank portion 106 and the second partial length L2 begins ata second distance D2 from the proximate end 112 of the shank portion106. Preferably, a difference between the first distance D1 and thesecond distance D2 is equal to about a thread pitch distance (i.e.,about the distance the screw 100 travels along longitudinal axis LA forone rotation of bone screw 100).

Referring to FIGS. 5 and 6, the exterior surface 118 of the shankportion 106 can include a channel 140 therein that extends between afirst one of the bone material apertures (e.g., the bone materialaperture 134) and a second one of the bone material apertures (e.g., thebone material aperture 136). The channel 140 in combination with thebone material apertures 134, 136 jointly form a contiguous bone materialwindow 142 having opposing side walls 144, 146 and a bridge member 148attached therebetween. With respect to clockwise rotation of the bonescrew 100 (i.e., screw insertion rotation direction), a first one of theopposing side walls (i.e., first opposing side wall 144) of the bonematerial window 142 defines a leading edge of the bone material window142 and a second one of the opposing side walls (i.e., second opposingside wall 146) of the bone material window 142 defines a trailing edgeof the bone material window 142.

As best shown in FIG. 6, in preferred embodiments, leading edge faces148 of the thread 116 are reclined with respect to the first opposingside wall 144 (i.e., leading edge) of the bone material window 142.Advantageously, such reclining of the leading edge faces 148 of thethread 116 serves to promote harvesting of bone fragments (e.g.,particles) generated from insertion of the bone screw 100 (i.e.,self-harvesting functionality). Specifically, relative to a minimumwidth W1 of the bone material window 142, the reclined leading edgefaces 148 of the thread 116 provides an effective width W2 that isgreater than the minimum width W1 of the bone material window 142. Thebenefit of increasing the width of the bone material window 142 is thatthe width of the bone material window 142 is proportional to a magnitudeof thread depth differential created at a bone location that the threadmoves past as the bone screw 100 is being placed (i.e., particularly ata portion of the bone screw 100 that is tapered (e.g., nearer to thedistal end 112)). In this manner, increasing the effective width W2 ofthe bone material window 142 promotes/increases harvesting of bonefragments in response to placement of the bone screw 100. In a preferredembodiment, the minimum width of the bone material window 142 (e.g.,within the bone material apertures 134, 136) can be equal to about thethread pitch distance and the leading edge faces 148 of the thread 116are reclined such that a transverse tip-to-tip distance (i.e., aboutequal to the effective width W2 of the bone material window 142) is atleast about 25% greater than the minimum width W1 of the bone materialwindow 142.

In preferred embodiments, the shank portion 106 and the head portion 108of the threaded fastener 103 are a one-piece component with the cap 104mounted thereon (e.g., passed over the shank portion 106 and snappedonto the head portion 108). The shank portion 106, the head portion 108and the cap 104 can be made from a suitable metallic material, suitablepolymeric material or a combination thereof. Examples of such suitablemetallic materials include stainless steel and titanium. An example of asuitable polymeric material includes PEEK (Polyether ether ketone)polymer. Bone screws configured in accordance with embodiments of thepresent invention are not unnecessarily limited to being made from anyspecific material.

Turning now to FIGS. 9-13, various aspects of a screw manipulation tool200 in accordance with an embodiment of the present invention are shown.The screw manipulation tool 200 is used by a surgeon to place one ormore bone screws configured in accordance with an embodiment of thepresent invention. Advantageously, the screw manipulation tool 200 canbe used for placing such a bone screw and/or can be used for extracting(i.e., removing) such a bone screw. As discussed above, thetorque-applying structure 102 of the bone screw 100 (i.e., a bone screwsconfigured in accordance with an embodiment of the present invention) isconfigured to allow the bone screw 100 to be both placed (i.e., rotatedin a first direction) and extracted (i.e., rotated in a second directionopposite the first direction) with a common tool (e.g., the screwmanipulation tool 200). The ability to extract the bone screw 100 withthe same tool used for placing it is highly beneficial due to timesavings during a surgical procedure and is advantageous with respect toprior art screw configurations that require placement and extractiontools to be differently configured.

The screw manipulation tool 200 includes a main housing 202, a lockmember control tube 204, a lock member control mechanism 206, a screwlock member 208 and a torque application drive member 209. The mainhousing 202 has a proximate end portion 210, a central portion 212 and adistal end portion 214. The proximate end portion 210, the centralportion 212 and the distal end portion 214 jointly define a centralpassage having the lock member control tube 204 rotatably mountedtherein with a proximate end portion of the lock member control tube 204at the proximate end portion 210 of the main housing 202 and a distalend portion of the lock member control tube 204 at the distal endportion 214 of the main housing 202.

As best shown in FIGS. 10, 11 and 13, the distal end portion 214 of themain housing 202 terminates at a tip portion 215 having across-sectional profile at its exterior surface that is matinglyengageable the tool interface structure 102. To this end, thecross-sectional profile of the tool interface structure 102 can be aprofile commonly referred to as a Phillips drive, a Torx drive, an Allen(i.e., hex) drive, a square drive or the like. The screw lock member 208is attached to the lock member control tube 204 at the distal endportion of the lock member control tube 204 (i.e., adjacent to thedistal end portion 214 of the main housing 202). The screw lock member208 is shaped to allow an engagement portion 216 of the screw lockmember 208 to be engaged within a tool lock recess 128 of the bone screw100. In preferred embodiments, the bone screw 100 includes a pluralityof tool lock recess 128 and the screw lock member 208 includes aplurality of engagement portions 216 each engageable with a respectiveone of the tool lock recesses 128 through rotation of the lock membercontrol tube 204. Through such engagement of the engagement portion(s)216 with the tool lock recess(es) 128, the bone screw 100 can be securedonto the distal end portion 214 of the main housing 202 thereby allowingrotation of the bone screw 100 in a clockwise and counter-clockwisedirections and allowing the bone screw 100 to be moved into a placementlocation or removed from a placement location.

The lock member control mechanism 206 provides for the screw lock member208 to be selectively moved (e.g., rotated) between a screw unlockposition (FIG. 10) and a screw lock position (FIG. 11) with respect tothe tip portion 215 of the main housing 202. In preferred embodiments,the lock member control mechanism 206 is moveably mounted on the mainhousing 202 and has a portion thereof (not shown) engaged with the lockmember control tube 204. Movement of the lock member control mechanism206 between a first position and a second position causes the screw lockmember 208 to correspondingly move between the screw unlock position(i.e., an orientation enabling the engagement portion(s) 216 of thescrew lock member 208 to be engaged with the tool lock recess(es) 128 ofthe bone screw 100) and the screw lock position (i.e., an orientationenabling the engagement portion(s) 216 of the screw lock member 208 tobe disengaged with the tool lock recess(es) 128 of the bone screw 100).

As shown in FIGS. 9 and 12, the torque application drive member 209 canbe attached to the lock member control tube 204 at the proximate endportion of the lock member control tube 204 (i.e., adjacent to theproximate end portion 210 of the main housing 202). The torqueapplication drive member 209 is preferably affixed to the lock membercontrol tube 204 such that rotation of the torque application drivemember 209 causes a corresponding rotation of the lock member controltube 204. A skilled person will understand that, in some embodiments,the torque application drive member 209 can be a feature machined into asurface of the lock member control tube 204.

Although the invention has been described with reference to severalexemplary embodiments, it is understood that the words that have beenused are words of description and illustration, rather than words oflimitation. Changes may be made within the purview of the appendedclaims, as presently stated and as amended, without departing from thescope and spirit of the invention in all its aspects. Although theinvention has been described with reference to particular means,materials and embodiments, the invention is not intended to be limitedto the particulars disclosed; rather, the invention extends to allfunctionally equivalent technologies, structures, methods and uses suchas are within the scope of the appended claims.

What is claimed is:
 1. A bone screw, comprising: a shank portion havinga proximal end and a distal end, wherein the shank portion includes atleast one thread on an exterior surface thereof extending from adjacentthe proximal end of the shank portion to adjacent the distal end of theshank portion; and a head portion attached to the shank portion at theproximate end thereof, wherein the head portion includes a toolinterface structure therein and wherein the tool interface structureincludes a plurality of sidewalls, a floor and a tool lock recesslocated within at least one of the sidewalls.
 2. The bone screw of claim1 wherein: the head portion includes a tool interface structure thereinhaving a closed end portion, an open end portion and sidewall extendingtherebetween; and the tool lock recess is partially defined by a floorof the tool interface structure at the closed end portion thereof. 3.The bone screw of claim 1 wherein: the shank portion includes acannulation passage extending longitudinally therethrough; thecannulation passage defines an interior surface of the shank portion;the shank portion includes at least one bone material aperture thereinextending between the exterior surface of the shank portion and theinterior surface of the shank portion; the at least one bone materialaperture extends through the at least one thread over a first partiallength of the shank portion; the at least one thread extends over asecond partial length of the shank portion; the first partial length isshorter than the second partial length; the second partial lengthencompasses the first partial length; the first partial length begins ata first distance from the proximate end of the shank portion; the secondpartial length begins at a second distance from the proximate end of theshank portion; and the first distance is greater than the seconddistance.
 4. The bone screw of claim 3 wherein the first distance isequal to about a thread pitch distance of the at least one thread. 5.The bone screw of claim 3 wherein: the head portion includes a toolinterface structure therein having a closed end portion, an open endportion and sidewall extending therebetween; and the tool lock recess ispartially defined by a floor of the tool interface structure at theclosed end portion thereof.
 6. The bone screw of claim 1 wherein: theshank portion includes a cannulation passage extending longitudinallytherethrough; the cannulation passage defines an interior surface of theshank portion; the shank portion includes a plurality of bone materialapertures therein each extending between the exterior surface of theshank portion and the interior surface of the shank portion; and theexterior surface of the shank portion includes a channel thereinextending between a first one of the bone material apertures and asecond one of the bone material apertures thereby forming a contiguousbone material window having opposing side walls and a bridge memberattached therebetween.
 7. The bone screw of claim 1 wherein: the shankportion includes a cannulation passage extending longitudinallytherethrough; the cannulation passage defines an interior surface of theshank portion; the shank portion includes at least one bone materialaperture therein extending between the exterior surface of the shankportion and the interior surface of the shank portion such that anaperture sidewall is defined between the exterior surface of the shankportion and the interior surface of the shank portion; the at least onebone material aperture extends through the at least one thread over atleast a portion of an entire length of the shank portion; and one ormore leading edge faces of the at least one thread is reclined withrespect to the aperture sidewall.
 8. The bone screw of claim 6 wherein:a width of the at least one bone material aperture is equal to about athread pitch distance of the at least one thread; and the one or moreleading edge faces of the at least one thread is reclined such that atransverse tip-to-tip distance between opposing edge faces of the treadis at least about 25% greater than the thread pitch distance of the atleast one thread.
 9. The bone screw of claim 6 wherein: the head portionincludes a tool interface structure therein having a closed end portion,an open end portion and sidewall extending therebetween; and the toollock recess is partially defined by a floor of the tool interfacestructure at the closed end portion thereof.
 10. The bone screw of claim6 wherein: the shank portion includes a cannulation passage extendinglongitudinally therethrough; the cannulation passage defines an interiorsurface of the shank portion; the shank portion includes at least onebone material aperture therein extending between the exterior surface ofthe shank portion and the interior surface of the shank portion; the atleast one bone material aperture extends through the at least one threadover a first partial length of the shank portion; the at least onethread extends over a second partial length of the shank portion; thefirst partial length is shorter than the second partial length; thesecond partial length encompasses the first partial length; the firstpartial length begins at a first distance from the proximate end of theshank portion; the second partial length begins at a second distancefrom the proximate end of the shank portion; and the first distance isgreater than the second distance.
 10. A bone screw, comprising: a mainbody including a shank portion and a head portion attached to the shankportion, wherein the head portion includes a tool interface structuretherein having a closed end portion, an open end portion and sidewallextending therebetween, wherein a tool lock recess is provided in atleast one of the sidewalls of the tool interface structure; and a capmoveably attached to the head portion, wherein the tool interfacestructure is accessible through an opening within an exterior surface ofthe cap.
 11. The bone screw of claim 10 wherein: the head portionincludes a tool interface structure therein having a closed end portion,an open end portion and sidewall extending therebetween; and the toollock recess is partially defined by a floor of the tool interfacestructure at the closed end portion thereof.
 12. The bone screw of claim10 wherein: the shank portion includes a cannulation passage extendinglongitudinally therethrough; the cannulation passage defines an interiorsurface of the shank portion; the shank portion includes at least onebone material aperture therein extending between the exterior surface ofthe shank portion and the interior surface of the shank portion; the atleast one bone material aperture extends through the at least one threadover a first partial length of the shank portion; the at least onethread extends over a second partial length of the shank portion; thefirst partial length is shorter than the second partial length; thesecond partial length encompasses the first partial length; the firstpartial length begins at a first distance from the proximate end of theshank portion; the second partial length begins at a second distancefrom the proximate end of the shank portion; and the first distance isgreater than the second distance.
 13. The bone screw of claim 12wherein: the head portion includes a tool interface structure thereinhaving a closed end portion, an open end portion and sidewall extendingtherebetween; and the tool lock recess is partially defined by a floorof the tool interface structure at the closed end portion thereof. 14.The bone screw of claim 10 wherein: the shank portion includes acannulation passage extending longitudinally therethrough; thecannulation passage defines an interior surface of the shank portion;the shank portion includes at least one bone material aperture thereinextending between the exterior surface of the shank portion and theinterior surface of the shank portion such that an aperture sidewall isdefined between the exterior surface of the shank portion and theinterior surface of the shank portion; the at least one bone materialaperture extends through the at least one thread over at least a portionof an entire length of the shank portion; and one or more leading edgefaces of the at least one thread is reclined with respect to theaperture sidewall.
 15. The bone screw of claim 15 wherein: a width ofthe at least one bone material aperture is equal to about a thread pitchdistance of the at least one thread; and the one or more leading edgefaces of the at least one thread is reclined such that a transversetip-to-tip distance between opposing edge faces of the tread is at leastabout 25% greater than the thread pitch distance of the at least onethread.
 16. The bone screw of claim 15 wherein: the head portionincludes a tool interface structure therein having a closed end portion,an open end portion and sidewall extending therebetween; and the toollock recess is partially defined by a floor of the tool interfacestructure at the closed end portion thereof.
 17. The bone screw of claim15 wherein: the shank portion includes a cannulation passage extendinglongitudinally therethrough; the cannulation passage defines an interiorsurface of the shank portion; the shank portion includes at least onebone material aperture therein extending between the exterior surface ofthe shank portion and the interior surface of the shank portion; the atleast one bone material aperture extends through the at least one threadover a first partial length of the shank portion; the at least onethread extends over a second partial length of the shank portion; thefirst partial length is shorter than the second partial length; thesecond partial length encompasses the first partial length; the firstpartial length begins at a first distance from the proximate end of theshank portion; the second partial length begins at a second distancefrom the proximate end of the shank portion; and the first distance isgreater than the second distance.
 18. A bone screw, comprising: a shankportion having at least one helically shaped thread on an exteriorsurface thereof, wherein the thread extends from adjacent a proximal endof the shank portion to adjacent a distal end of the shank portion,wherein the shank portion includes a cannulation passage extendinglongitudinally therethrough, wherein the cannulation passage defines aninterior surface of the shank portion, wherein the shank portionincludes at least one bone material aperture therein extending betweenthe exterior surface of the shank portion and the interior surface ofthe shank portion such that an aperture sidewall is defined between theexterior surface of the shank portion and the interior surface of theshank portion; a head portion attached to the shank portion at theproximal end thereof, wherein the head portion includes a tool interfacestructure therein, wherein the tool interface structure includes aclosed end portion, an open end portion and sidewalls extendingtherebetween, wherein the tool interface structure includes a tool lockenabling feature provided in at least one of the sidewalls thereof andwherein the cannulation passage is exposed at the closed end portion ofthe tool interface structure; and a cap moveably attached to the headportion, wherein the tool interface structure is accessible through anopening within an exterior surface of the cap.
 20. The bone screw ofclaim 19 wherein: the at least one bone material aperture extendsthrough the at least one thread over at least a portion of an entirelength of the shank portion; a width of the at least one bone materialaperture is equal to about a thread pitch distance of the at least onethread; and one or more leading edge faces of the at least one thread isreclined with respect to the aperture sidewall such that a transversetip-to-tip distance between opposing edge faces of the tread is at leastabout 25% greater than the thread pitch distance of the at least onethread.